My Kitty is sick...

I have a major coolant leak at the rear of the engine. I cannot see it from the top but it presents itself as a leak at the bottom of the transmission where it looks as if it is leaking directly from where the transmission joins the engine block.

I have read in another thread where the heater hose connections are the most likely culprit and I hope this is the case. However, having dealt with rotating machinery that has attached pumps, I am suspicious of the attached tranmission cooling pump and that it has possibly failed. Considering the fact that I don't see the leak until the engine reaches operating temperature (around 180 degrees), I suspect it is most likely not the attached transmission pump but would love some expertise to rule that out.

If anyone can shed some light, give me some tips, show me some pictures (most preferred), show up in my driveway to give me guidance (would really love this), I would be most appreciative.

 

There are a number of threads on the heater hose that is under the intake that you should be able to find using search that may be helpful to you. Especially for the XJR. If it is that hose, it involves removing the supercharger.

Have you unfastened the rear bulkhead cover to get a better look while running?

If it only appears under pressure, a pressure tester may be helpful in finding it. Also look for dried antifreeze trails.

There is no transmission cooling pump as such.

 

As stated above, there is no transmission cooling pump-but there is a heater water pump & valve assembly below the coolant expansion tank with various heater hoses attached.

The long heater hoses pass under the supercharger, so that will need to be removed along with the 2 chargecoolers either side in order to access the hoses, if you have to replace them.

But before you do that, remove the long plastic rear central bulkhead cover. It's at the back of the engine bay at the top & fastened by a single plastic screw. It goes over the coolant filler cap & expansion tank so you can't miss it-it's not hard to remove if you're careful & only takes a few seconds to do.

Once you've rotated the plastic screw & pulled it out, you'll need to wiggle the big plastic cover piece upwards, taking care not to damage the small plastic coolant pipes that come from the expansion tank-it's very easy to do if you're not slow & methodical when removing the cover.

Once you've removed this cover piece, you've got a much better view of the back of the engine & the bulkhead, so you should be able to see much better when examining for leaks in that area. If the heater hoses feel squishy & soft, then they've almost certainly failed & caused the leak.

Much as I'd like to pop round to assist, I'm on the other side of the Atlantic

 

It does not appear to be the heater hoses, was one of those things I thought of considering the amount of disassembly required to change them and, well, my luck.

Yes, I did, the first thing.

I did look for trails, I really didn't see any. The leak appears to be on the (US) passenger side.

The repair manual I have says: "The transmission fluid cooling system maintains the fluid temperature within specified limits. The cooling element is located in the engine cooling radiator LH end tank. Fluid is circulated, under pressure, by the transmission pump to the cooler."

I'm going to guess, after further pondering, that means the transmission oil is circulated out for cooling instead of using coolant circulated through the transmission. That would make more sense, I suppose, than running the risk of cross contaminating the transmission.

 

Are you sure you don't want to come on by? I'll be more than happy to feed you all of the ribeye steak and your choice of beer that you want.

I have removed the center cover piece as well as the (US) passenger side cover piece. The only place I see the leak is under the car as all of that expensive coolant runs off of the joint where the transmission mates up to the engine. At the top of the engine, I don't see where it is coming from. Since the leak appears to be on the passenger side, I didn't look too hard at the drivers side where the matrix and electric pump are situated.

Anything else?

 

Mmm steak & beer-the staple diet in the North of England

As stated by plums, there is no transmission cooling pump & no coolant is pumped to the gearbox. The reverse is true, as the gearbox internal hydraulic pump pumps hot gearbox fluid to the transmission oil cooler in the main coolant radiator, where it is cooled & then circulates back into the gearbox.

There's no quick way to trace a coolant leak if it's not obvious-you have to slowly & methodically examine all the coolant pipes in the area-there are quite a lot of them around the electric pump & valve under the coolant expansion tank. The coolant expansion tank itself may be leaking-they can do this.

There's not a lot of space around the rear of the engine to work & there are a couple of heater hoses that come from the front of the engine & pass under the supercharger to the hear pipes at the rear of the engine.

Either way, you're going to have to remove the supercharger & 2 chargecoolers either side of it-to make room both for examination of the heater hoses there & for replacement. Once you've removed these parts then you've got more room for examination it should be easier to locate the leak.

I have a friend in the US, in the Cincinnati, Ohio area-he's just done this operation to his own 2000 XJR & is a member of this forum (member: bergxu). He has a couple of pictures of the process showing the top of the engine with the supercharger & chargecoolers removed, exposing the heater hose & layout.

You could find his profile here & send him a message.

 

If you can see coolant coming from under the supercharger it will be one of the two heating hoses that run under the supercharger. There is also a coolant hose on the throttle body in the area that you suspect.

Removing the supercharger is a *lot* of work, so you want to be sure.

Perhaps you could inspect using a borescope or mirror and flashlight to get the right viewing angle. This is best done at night or indoors so that the inspection area is brighter than the surroundings.

 

Funny thing is that I have just had mine do the same thing...the hose under the supercharger has a slow leak. I have been told that to replace all the coolant hoses will cost approx $1700! I wish I had done this when I had the head gasket done a few years back.

 

I just did every single heater hose on my '00 XJR. Took the s/c off, did the ones underneath it, as well as the big "octopus" hose at the very rear of the engine, among some smaller ones at the water outlet up front, etc... For the longest time, I was also getting those small "double drips" which ran down the bellhousing, throwing me off as to where the leak originated. Last time I had the car on my lift, I finally gave a good long look around the bellhousing and saw that octopus hose was the culprit. Figured since it had to be done, I may as well just do everything at once, so a big order was placed and in an afternoon everything was sorted. Result!

 

So I had the hose that runs under the SC changed and I drove the car back home only to notice that it is still leaking. Arrrrh! I got back under there and noticed that the octopus hose was now leaking under pressure where it wasn't before. I have attached the pic.

I am now in the process of getting this replaced and hopefully this will be the end of my heater hose issues.

Bergxu- it would be interesting to know how long it took you to change the octopus hose, I cant seem to find instructions on how to do it anywhere.

 

Pookie;

Well, I didn't do it myself. Had a mate of mine who's a mechanic for the local Jag dealer come by and replace everything for a 12-pack of his favorite...

 

I would do a bunch of stuff all at the same time (and may need to here shortly..I have a leak)
1. supercharger oil
2. gaskets
3. clean TB
4. hoses under the manifold

 

Guys, I appreciate all of the support and wisdom. I am finally in a position to be able to get this stupid thing repaired after a brutal financial fall/winter. It looks as if the leak is coming from the (US) passenger side heater feed hose that runs in the V under the intake/super charger. Does anyone know whether or not this hose can be pulled through the V instead of pulling the top end apart?

I will also start the car and do a more thorough inspection of the EGR and TB connections as well.

If anyone has any pictures other than what has been posted to share with me, and any more direct instructions for this poor noob, I sure would appreciate it.

Pookie, I am very worried that I am going to end up with more leaking hoses when I replace the one that is currently leaking...

 

If we are talking about the Spider (or Octopus) hose, then you don't need to remove the SC for its replacement. But the job is PIA.

 

Hi,
It could also be the thermostat tower, this is fitted with an O ring at the base and this can/will age and cause it to leak, the leaking coolant runs in the V of the engine and drips from the engine / trans. joint. If you decide to do this job you should consider fitting a new alloy tower which should last a good few years. When I did mine I took the inlet manifold off which makes it much easier to get at the tower fixing bolts. Hope this helps.

 

Except for the fact that the said tower does not exist on a XJR.

 

Thanks to Plums for pointing out my error, I had assumed the engine layout was the same as my XJ8, obviously not. I hope the problem is soon resolved.

 

Forum member Safi just completed replacing the Octopus heating hose and started a new forum thread with DIY instructions and photos.

Here is the weblink to his new forum thread:
https://www.jaguarforums.com/forum/x...-repair-93451/

This Octopus hose has 5 connectors, one of them does connect to one of the hoses that goes under the intake manifold.

Jim Lombardi

 

Thanks for taking the time to try and help.

 

Thanks, but is this going to be the same as the XJR? The diagrams seem to show a bit of a difference between the two.